Recent advances in electrophysiological research have led to the description of a self-monitoring system specialized in error detection. These studies describe a specific component of event-related brain potentials (ERP) that emerges approximately 60-80 milliseconds after an error has been committed. This component is referred to as error-related negativity. Further, preliminary evidence suggests that patients with schizophrenia have smaller ERN amplitudes than normal controls. These data represent important advances in our understanding of the pathophysiology of schizophrenia as we become increasingly aware of dysfunctions not only in sensory processing but also in response monitoring as possible contributors in explanatory models of symptoms and cognitive deficits. Recent work also suggests that cognitive impairments are a core feature of schizophrenia, providing the best predictor of disorder outcome and functional impairments. Though traditional neuropsychological testing can reliably assess cognitive performance, little is understood about the exact physiologic substrates of the cognitive impairments in schizophrenia. The current project offers the promise of linking neurophysiological brain measures relating to error detection and self monitoring to impairments in neuropsychological measures.